Replace chrome trap arm under kitchen sink

Hi all,
I started replacing kitchen sink plumbing and stuck, because I am not sure how to remove the trap arm to replace it with PVC part.
Looks like it is either soldered or glued into some kind of fitting inside the elbow. At the wall side the elbow seems to be screwed into the waste pipe.
Please advice.
Thanks!

You should be able to unscrew that fitting from the portion sticking out of the wall. It is preferable to only use male plastic threaded fittings, because if you get it too tight with a female, it may end up splitting down the road (if it doesn't happen right away). With a male plastic bit, the metal female helps prevent it from splitting. It is possible that the nipple through the wall may unscrew from the fitting behind. This normally isn't catastrophic, but you'd need to clean it off and then put pipe dope or teflon tape on it before screwing it back in. That looks like concrete, so if it is, it probably won't budge when removing the coupling from the threaded nipple.

Normally you'd screw on a Desanko (it is called other things in various parts of the country, and then the tubular trap arm would slide into it, you then tighten up the compression nut on the Desanko, and you're done. WIthout seeing the whole shebang, it's hard to tell if you need that 22-degree offset or can just use a straight fitting.

One side is soldered, you won't get that out...the other end is threaded onto the nipple...that should unscrew. Now, it's possible that the solder made it into the threads of the back part, then, all bets are off. That nipple may screw out of the fitting behind it, and if required, you could install a new one if you can't get that fitting off.

One side is soldered, you won't get that out...the other end is threaded onto the nipple...that should unscrew. Now, it's possible that the solder made it into the threads of the back part, then, all bets are off. That nipple may screw out of the fitting behind it, and if required, you could install a new one if you can't get that fitting off.

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The way they were installed was to solder the bushing onto the trap before screwing it in. There should be no solder behind the bushing. But in most cases it will have to be cut out.